"The building wasn't on the list of dilapidated buildings," Mumbai Mayor Vishwanath Mahadeshwar told reporters on Tuesday.

"We will investigate whether the building fell because of an alteration in the structure."

Search and rescue operations went on amid sporadic rain showers on Wednesday.

"There was a hospital at the basement of the building that was conducting renovation work, which could have led to the collapse of the building," Prakash Mehta, housing minister for the western state of Maharashtra, told reporters.

The chief minister of Maharashtra state, of which Mumbai is the capital, ordered an investigation into the latest incident after reports that renovation work was going on at the site at the time of the collapse.

Mumbai is particularly vulnerable with millions forced to live in cramped, ramshackle properties because of rising property prices and a lack of housing for the poor.

A dilapidated building left 12 people dead when it collapsed near the city in August 2015. Nine people died the same month when another old three-storey building collapsed in monsoon rain in the Mumbai suburb of Thakurli.

In 2013, 60 people were killed when a residential block came crashing down in one of Mumbai's worst housing disasters.